Hypertrophic cardiomyopathy, characterised by unexplained cardiac hypertrophy, is the commonest inherited cardiac condition (prevalence ˜0.2%). The clinical manifestations of HCM can range from the complete absence of symptoms to dyspnoea, chest pains, palpitations, and syncope; HCM's first presentation may even be as sudden cardiac death. Left ventricular outflow tract obstruction that accounts for some of these symptoms in a proportion of HCM patients, may be amenable to drug therapies and to interventions such as surgical septal myectomy or alcohol septal ablation. However, less progress has been made, in the treatment of the substantial number of patients with HCM without obstruction, in whom dyspnoea appears to be primarily due to diastolic dysfunction. Evidence supporting the benefit of the negative chrono-inotropes (eg, beta-blockers, verapamil, disopyramide), which are extensively used by these patients, is limited mandating a better understanding of the mechanisms underlying HCM with the intention of identifying novel therapies.
HCM is a disease of the perturbed sarcomere, with >400 mutations having been identified in genes encoding cardiac contractile proteins (e.g. β-myosin heavy chain, cardiac myosin-binding protein-C, α-tropomyosin, cardiac troponin T and I). HCM-causing mutations increase sarcomeric Ca2+ sensitivity, ATPase activity and the energetic “tension cost” of myocyte contraction. These biophysical considerations have led to the proposal that the pathophysiology of HCM is attributable, at least in part, to excessive sarcomeric energy use. Supporting this proposal, myocardial energy defects have been associated with HCM, in both animal and human disease. Indeed, consistent with a functional role for this energy deficiency, LV relaxation (an energy requiring process), has been observed to be aberrant in HCM.
Perhexiline (2-(2,2-dicyclohexylethyl) piperidine) is a known anti-anginal agent that operates principally by virtue of its ability to shift metabolism in the heart from free fatty acid metabolism to glucose, which is more energy efficient.
WO-A-2005/087233 discloses the use of perhexiline for the treatment of chronic heart failure (CHF) where the CHF is a result of an initial inciting influence of ischaemia or where the CHF is a result of an initial non-ischaemic inciting influence.